CA2568291C - Handover execution and communication resumption in wireless access system - Google Patents
Handover execution and communication resumption in wireless access system Download PDFInfo
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- CA2568291C CA2568291C CA2568291A CA2568291A CA2568291C CA 2568291 C CA2568291 C CA 2568291C CA 2568291 A CA2568291 A CA 2568291A CA 2568291 A CA2568291 A CA 2568291A CA 2568291 C CA2568291 C CA 2568291C
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- 238000004891 communication Methods 0.000 title claims abstract description 82
- 238000000034 method Methods 0.000 claims abstract description 103
- 230000000717 retained effect Effects 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 12
- 238000012790 confirmation Methods 0.000 description 7
- 238000007781 pre-processing Methods 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000977 initiatory effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000013475 authorization Methods 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 238000010187 selection method Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/26—Reselection being triggered by specific parameters by agreed or negotiated communication parameters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0055—Transmission or use of information for re-establishing the radio link
- H04W36/0079—Transmission or use of information for re-establishing the radio link in case of hand-off failure or rejection
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/08—Reselecting an access point
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/16—Performing reselection for specific purposes
- H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/34—Reselection control
- H04W36/36—Reselection control by user or terminal equipment
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- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
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Abstract
Handover execution and communication resumption in a wireless access system is provided. Performing a handover includes communicating with a serving base station through a first communication link and receiving from the serving base station, handover information associated with at least one candidate target base station. The method also includes transmitting handover indicator to the serving base station indicating a handover operation to a selected target base station and performing a ranging procedure with the selected target base station to establish a second communication link with the selected target base station while maintaining the first communication link with the serving base station. The method also includes being released from the serving base station in response to a handover complete status message from the selected target base station to the serving base station, or resuming normal communication with the serving base station if the handover fails with the selected target base station.
Description
HANDOVER EXECUTION AND COMMUNICATION RESUMPTION IN
WIRELESS ACCESS SYSTEM
[DESCRIPTION]
TECHNICAL FIELD
The present invention relates generally to a wireless access system, and more particularly to handover execution in a wireless access system.
BACKGROUND ART
The TEEE802.16e system is part of a global standardization for broadband wireless access systems. IEEE802.16e does not have a hierarchical structure of HLR, VLR, MSC, BSC, RNC, etc. unlike second and third generation mobile communications systems, but does include a mobile subscriber station (MSS), a base station (BS), and an authentication service authorization server (ASA server). A physical (PHY) layer and a medium access control (MAC) layer are defined between the BS and the MSS.
A handover process in a broadband wireless access system according to a related art is explained as follows.
1. Pre-processing for Handover Pre-processing for handover includes broadcasting associated information from a base station to a neighboring base station to inform all mobile subscriber stations within a respective cell of the associated information (Network Topology Advertisement). The pre-processing also includes measuring a channel quality of the neighboring base station based on the associated information (MSS Scanning of Neighboring BS). The pre-processing also includes matching parameters between the base station and the neighboring base station, such as for example, an initial mobile subscriber station power, a time difference for synchronization, and other parameters (Association Procedures).
a. Network Topology Advertisement In network topology advertisement, the base station broadcasts information associated with network configuration to all mobile subscriber stations within a cell via a MOB NBR-ADV MAC message, thereby providing all mobile subscriber stations within the cell with the information pertaining to neighboring base stations.
b. MSS Scanning of Neighboring BS
In MSS scanning of neighboring BS, a mobile subscriber station (MSS) scans a neighboring base station (BS) and requests a scanning interval for scanning the neighboring BS from the BS via a MOB SCN-REQ MAC message. The BS then transmits a MOB SCN-RSP MAC message in response to the request to assign an interval for scanning (scanning interval) the neighboring BS. Alternatively, the BS may directly transmit the MOB _ SCN_ RSP MAC message without a request from the MSS
(unsolicited response). In the case of an unsolicited response, the scanning interval and an offset unit for scanning start are assigned on a frame unit basis.
c. Association Procedures During association procedures, the MSS performs a ranging process with a BS to normally join a cell. In the ranging process, the MSS acquires basic information for communications from the BS. In other words, the MSS performs BS scanning to select a new BS and then performs the association procedures. The MSS and the BS
transmit a RNG_REQ MAC message and a RNG_RSP MAC message, respectively, to set values such as for example, a power offset value, a timing offset value, and other values of the MSS to suitable values. Transmission of the RNG REQ MAC message is called an initial ranging operation and is a basic operation that the MSS may perform in a network entry procedure.
When a handover is performed, a target BS accepts a new MSS and transmits items associated with the respective cell of the new MSS to the former serving BS
and stores information pertaining to the MSS.
2. Handover Process In a handover (HO) process, the MSS initiates handover with the neighboring BS
based on the channel quality information acquired in the handover pre-processing.
a. Cell Selection In a cell selection procedure, a cell is changed to enable the MSS to make a new registration to a BS, allowing for reception of a signal having an SINR
(signal to interference noise ratio) superior to that of a signal transmitted from the BS
of the current cell, prior to a normal registration of the MSS to a cell. In such case, since the MSS does not perform the registration procedure, the BS is unable to determine a moving situation of the MSS.
b. HO (handover) Initiation In HO initiation, a handover may be initiated by the MSS or the BS. When the BS
2 0 requests (initiates) a handover, the BS transmits a MOB_BSHO-REQ MAC
message to the MSS. On the contrary, when the MSS requests a handover, the MSS transmits a MOB MSSHO-REQ MAC message to the BS.
WIRELESS ACCESS SYSTEM
[DESCRIPTION]
TECHNICAL FIELD
The present invention relates generally to a wireless access system, and more particularly to handover execution in a wireless access system.
BACKGROUND ART
The TEEE802.16e system is part of a global standardization for broadband wireless access systems. IEEE802.16e does not have a hierarchical structure of HLR, VLR, MSC, BSC, RNC, etc. unlike second and third generation mobile communications systems, but does include a mobile subscriber station (MSS), a base station (BS), and an authentication service authorization server (ASA server). A physical (PHY) layer and a medium access control (MAC) layer are defined between the BS and the MSS.
A handover process in a broadband wireless access system according to a related art is explained as follows.
1. Pre-processing for Handover Pre-processing for handover includes broadcasting associated information from a base station to a neighboring base station to inform all mobile subscriber stations within a respective cell of the associated information (Network Topology Advertisement). The pre-processing also includes measuring a channel quality of the neighboring base station based on the associated information (MSS Scanning of Neighboring BS). The pre-processing also includes matching parameters between the base station and the neighboring base station, such as for example, an initial mobile subscriber station power, a time difference for synchronization, and other parameters (Association Procedures).
a. Network Topology Advertisement In network topology advertisement, the base station broadcasts information associated with network configuration to all mobile subscriber stations within a cell via a MOB NBR-ADV MAC message, thereby providing all mobile subscriber stations within the cell with the information pertaining to neighboring base stations.
b. MSS Scanning of Neighboring BS
In MSS scanning of neighboring BS, a mobile subscriber station (MSS) scans a neighboring base station (BS) and requests a scanning interval for scanning the neighboring BS from the BS via a MOB SCN-REQ MAC message. The BS then transmits a MOB SCN-RSP MAC message in response to the request to assign an interval for scanning (scanning interval) the neighboring BS. Alternatively, the BS may directly transmit the MOB _ SCN_ RSP MAC message without a request from the MSS
(unsolicited response). In the case of an unsolicited response, the scanning interval and an offset unit for scanning start are assigned on a frame unit basis.
c. Association Procedures During association procedures, the MSS performs a ranging process with a BS to normally join a cell. In the ranging process, the MSS acquires basic information for communications from the BS. In other words, the MSS performs BS scanning to select a new BS and then performs the association procedures. The MSS and the BS
transmit a RNG_REQ MAC message and a RNG_RSP MAC message, respectively, to set values such as for example, a power offset value, a timing offset value, and other values of the MSS to suitable values. Transmission of the RNG REQ MAC message is called an initial ranging operation and is a basic operation that the MSS may perform in a network entry procedure.
When a handover is performed, a target BS accepts a new MSS and transmits items associated with the respective cell of the new MSS to the former serving BS
and stores information pertaining to the MSS.
2. Handover Process In a handover (HO) process, the MSS initiates handover with the neighboring BS
based on the channel quality information acquired in the handover pre-processing.
a. Cell Selection In a cell selection procedure, a cell is changed to enable the MSS to make a new registration to a BS, allowing for reception of a signal having an SINR
(signal to interference noise ratio) superior to that of a signal transmitted from the BS
of the current cell, prior to a normal registration of the MSS to a cell. In such case, since the MSS does not perform the registration procedure, the BS is unable to determine a moving situation of the MSS.
b. HO (handover) Initiation In HO initiation, a handover may be initiated by the MSS or the BS. When the BS
2 0 requests (initiates) a handover, the BS transmits a MOB_BSHO-REQ MAC
message to the MSS. On the contrary, when the MSS requests a handover, the MSS transmits a MOB MSSHO-REQ MAC message to the BS.
If the MSS transmits the MOB _MSSHO-REQ MAC message, the MSS preferentially transmits the SINR of a signal received from a neighboring BS to the BS to enable the MOB _MSSHO-REQ MAC message to be transmitted to a current serving BS. The current serving BS then selects a candidate BS as a target BS for performing the handover.
In a case where the BS receives the MOB_ MSSHO-REQ MAC message from the MSS or in a case when the BS has not yet transmitted the MOB_BSHO-REQ MAC
message to handover the MSS, the BS may allow the handover of the MSS after confirmation of an acknowledgement (ACK) for handing over a specific MSS from the neighboring BS. After receiving the MOB_BSHO/MSSHO-REQ MAC message, the MSS/BS transmits a MOB _MSSHO/BSHO-RSP MAC message to inform the BS/MSS of a target BS for the handover.
c. HO Cancellation In HO cancellation, after the MSS/BS transmits the MOB_MSSHO/BSHO-REQ
MAC message, the MSS may cancel the handover. In canceling the HO, the MSS
sets a specific field (HO_Type=01) of a MOB_HO-IND MAC message and transmits the set field to the BS. The BS receives the message and cancels the proceeding handover.
d. Termination with the Serving BS
In termination with the serving BS, the MSS transmits the MOB_HO-IND MAC
message to inform the serving BS that the handover is normally completed and then completes the handover operation. In completing the handover operation, the MSS sets a specific field (HO_Type=00) of the MOB_HO-IND MAC message to transmit the information pertaining to the normal handover termination to the serving BS.
The serving BS receives the MOB HO-IND MAC message from the MSS and terminates a MAC state machine allocated to the MSS. The serving BS also terminates an ARQ (automatic repeat request) connection and all connections associated with data transmission.
e. HO Rejection 5 In HO
rejection, the MSS is capable of rejecting a handover recommended by the BS.
In rejecting a handover, the MSS sets a specific field (HO_Type=10) of the MOB_HO-IND
MAC message and transmits the message to the BS. The BS receives the rejection message from the MSS, re-seeks for a target BS and re-transmits the MOB_BSHO-RSP MAC
message to the MSS.
1 0 FIG.
1 is a diagram illustrating a handover process requested by a mobile subscriber station (MSS).
Referring to FIG. 1, an MSS 11 performs a scanning procedure to measure qualities of signals transmitted from neighboring BSs (S110). If the MSS 11 determines that a handover needs to be performed based on results of the neighboring BS scanning procedure, the MSS
1 1 transmits a handover request message (MOB-MSS-HO-REQ) to a serving BS 12 (S111).
The serving BS 12 receives the handover request message and transmits a handover pre-notification message (HO-pre-notification) including information that the MSS 11 has requested a handover to a neighboring BS, such as for example, handover target BSs (target BSs) 13 and 14 (S112, S113). The handover pre-notification message includes an identifier 2 0 (MSS
identifier) of the MSS 11 requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 13 and 14 receives the handover pre-.
In a case where the BS receives the MOB_ MSSHO-REQ MAC message from the MSS or in a case when the BS has not yet transmitted the MOB_BSHO-REQ MAC
message to handover the MSS, the BS may allow the handover of the MSS after confirmation of an acknowledgement (ACK) for handing over a specific MSS from the neighboring BS. After receiving the MOB_BSHO/MSSHO-REQ MAC message, the MSS/BS transmits a MOB _MSSHO/BSHO-RSP MAC message to inform the BS/MSS of a target BS for the handover.
c. HO Cancellation In HO cancellation, after the MSS/BS transmits the MOB_MSSHO/BSHO-REQ
MAC message, the MSS may cancel the handover. In canceling the HO, the MSS
sets a specific field (HO_Type=01) of a MOB_HO-IND MAC message and transmits the set field to the BS. The BS receives the message and cancels the proceeding handover.
d. Termination with the Serving BS
In termination with the serving BS, the MSS transmits the MOB_HO-IND MAC
message to inform the serving BS that the handover is normally completed and then completes the handover operation. In completing the handover operation, the MSS sets a specific field (HO_Type=00) of the MOB_HO-IND MAC message to transmit the information pertaining to the normal handover termination to the serving BS.
The serving BS receives the MOB HO-IND MAC message from the MSS and terminates a MAC state machine allocated to the MSS. The serving BS also terminates an ARQ (automatic repeat request) connection and all connections associated with data transmission.
e. HO Rejection 5 In HO
rejection, the MSS is capable of rejecting a handover recommended by the BS.
In rejecting a handover, the MSS sets a specific field (HO_Type=10) of the MOB_HO-IND
MAC message and transmits the message to the BS. The BS receives the rejection message from the MSS, re-seeks for a target BS and re-transmits the MOB_BSHO-RSP MAC
message to the MSS.
1 0 FIG.
1 is a diagram illustrating a handover process requested by a mobile subscriber station (MSS).
Referring to FIG. 1, an MSS 11 performs a scanning procedure to measure qualities of signals transmitted from neighboring BSs (S110). If the MSS 11 determines that a handover needs to be performed based on results of the neighboring BS scanning procedure, the MSS
1 1 transmits a handover request message (MOB-MSS-HO-REQ) to a serving BS 12 (S111).
The serving BS 12 receives the handover request message and transmits a handover pre-notification message (HO-pre-notification) including information that the MSS 11 has requested a handover to a neighboring BS, such as for example, handover target BSs (target BSs) 13 and 14 (S112, S113). The handover pre-notification message includes an identifier 2 0 (MSS
identifier) of the MSS 11 requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 13 and 14 receives the handover pre-.
notification message and transmits a handover pre-notification response message (HO-pre-notification-response) to the serving BS 12 in response to the handover pre-notification message (S114, S115). The handover pre-notification response message may include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 12 selects one of the neighboring handover target BSs 13 and 14 according to the response messages for the handover pre-notification and transmits a handover confirm message (HO-confirm) to the selected target BS 13 or 14 (S116). The serving BS 12 then transmits a handover response message (MOB-BSHO-RSP), including information pertaining to the selected handover target BS, to the MSS 11 (S117). The MSS
11 receives the handover response message and transmits a handover indicator message (MOB-HO-IND) to release a connection from the MSS 11 to the serving BS 12 (S118).
Upon receipt of the handover indicator message from the MSS 11, the serving BS
releases its connection to the MSS 11 (S119).
1 5 The MSS 11 then executes a fast ranging (Fast Ranging_IE), a ranging request (RNG-REQ), and a ranging response (RNG-RSP) with the target BS 14 (S120, S121, S122). The target BS 14 becomes the serving BS 14 and the MSS 11 completes an initial network entry execution after handover (S123).
FIG. 2 is a diagram illustrating a handover process requested by a base station (BS).
2 0 Referring to FIG. 2, a serving BS 22 triggers a procedure (trigger-to-release-MSS) to release a connection from an MSS 21 according to a corresponding decision (S210).
The serving BS 22 then transmits a handover pre-notification message (HO-pre-notification) including information required for the handover of the MSS 21 to neighboring handover target BSs 23 and 24 (S211, S212). The handover pre-notification message includes an identifier (MSS identifier) of the MSS 21 requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 23 and 24 receive the handover pre-notification message and transmit a handover pre-notification response message (HO-pre-notification-response) to the serving BS 22 in response to the handover pre-notification message (S213, S214). The handover pre-notification response message may include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 22 then transmits a handover request message to the MSS 21 based on the information received via the handover pre-notification response message (S215). The handover request message includes information pertaining to the target BSs 23 and 24 available for the handover. The MSS 21 then performs a neighboring BS scanning 1 5 procedure to measure quality of signals received by the neighboring target BSs, as recognized via a handover response message (S216). In a case where the target BS 24 is found for the handover is found as a result of the neighboring BS scanning, the MSS 21 transmits a handover response message including target BS information for the handover to the serving BS 22 (S217). The serving BS 22 then transmits a handover confirm message to 2 0 the target BS 24 to which the MSS 21 intends to perform the handover (S218).
The MSS 21 then transmits a handover indicator message (MOB-HO-IND) for releasing a connection from the MSS 21 to the serving BS 22 (S219). Upon receipt of the handover indicator message, the serving BS 22 releases its connection to the (S220).
The MSS 21 then executes a fast ranging (Fast Ranging_IE), a ranging request (RNG-REQ), and a ranging response (RNG-RSP) (S221, S222, S223) with the serving target BS
24 for the handover and then completes an initial network entry execution after handover (S224).
FIG. 3 is a diagram illustrating a process by which an MSS re-enters a former serving BS, such as in the case of a call drop.
Referring to FIG. 3, an MSS 31 performs a scanning procedure to measure qualities of signals transmitted from neighboring BSs (S310). If the MSS determines that a handover needs to be performed based on results of the neighboring BS scanning procedure, the MSS
31 transmits a handover request message (MOB-MSS-HO-REQ) to a serving BS 32 (S311).
The serving BS 32 receives the handover request message and transmits a handover pre-notification message (HO-pre-notification) including information that the MSS 31 has requested a handover to a neighboring BS, such as for example, handover target BSs 33 and 34 (S312, S313). The handover pre-notification message includes an identifier (MSS
identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 33 and 34 receive the handover pre-2 0 notification message and transmit a handover pre-notification response message (HO-pre-notification-response) to the serving BS 32 in response to the handover pre-notification message (S314, S315). The handover pre-notification response message may include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 32 selects one of the neighboring handover target BSs 33 and 34 according to the response messages for the handover pre-notification and transmits a handover confirm message (HO-confirm) to the selected target BS 33 or 34 (S316). The serving BS 32 then transmits a handover response message (MOB-BSHO-RSP) including information pertaining to the target BS for the handover to the MSS 31 (S317).
The MSS
31 receives the handover response message from the serving BS 32 and transmits a handover indicator message (MOB-HO-IND) to release a connection from the MSS
31 to the serving BS 32 (S318). Upon receipt of the handover indicator message, the serving BS
32 releases its connection to the MSS 31 (S319).
SUMMARY
Accordingly, an embodiment of the present invention is directed to handover execution and communication resumption in a wireless access system that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An embodiment of the present invention may provide a method of efficiently resuming communications in a wireless access system when a mobile subscriber station (MSS) returns to a former serving base station (BS) in case of a handover failure.
Additional advantages, objects, and features will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
According to an aspect of the invention, there is provided a method of 5 performing handover operation in a wireless communication system, the method comprising:
communicating with a serving base station through a first communication connection using connection resources, wherein the serving base station retains the connection resources for a mobile subscriber station; receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover 10 response message comprises at least a quality of service capable of being handled by the at least one candidate target base station; determining whether to perform a handover operation in response to the handover response message; if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station; performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station;
transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection resources.
A further aspect of the invention provides a method of performing handover operation in a wireless communication system, the method comprising: receiving a handover request from a mobile subscriber station through a first communication connection using connection resources; transmitting a handover response message to the mobile subscriber station, wherein the handover response message is associated with at least one candidate target base station and comprises at least a quality of service capable of being handled by the 10a at least one candidate target base station; receiving a first handover indicator message from the mobile subscriber station indicating that the mobile subscriber station is to undergo a handover operation to a selected target base station of the at least one candidate target base station; retaining the connection resources related to the mobile subscriber station; receiving a second handover indicator message indicating a handover cancel upon failure of the mobile subscriber station to establish a second communication connection with the selected target base station; and after the receiving of the second handover indicator message, resuming normal communication with the mobile subscriber station using the retained connection resources.
There is also provided a mobile subscriber station in a wireless communication system, the mobile subscriber station comprising: means for communicating with a serving base station through a first communication connection, wherein the serving base station retains connection resources related to the mobile subscriber station; means for receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover response message comprises at least a quality of service capable of being handled by the at least one candidate target base station; means for determining whether to perform a handover operation in response to the handover response message; means for, if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station; means for performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station; means for transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and means for, after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection resources.
10b In one embodiment, a method of performing handover operation in a wireless communication system includes communicating with a serving base station through a first communication link and receiving from the serving base station, handover information associated with at least one candidate target base station, wherein the handover information comprises at least quality of service capable of being handled by the at least one candidate target base station. The method also includes transmitting a handover indicator to the serving base station indicating a handover operation to a selected target base station, wherein the mobile subscriber station determines whether to perform handover in response to the handover information, and performing a ranging procedure with the selected target base station to establish a second communication link with the selected target base station while maintaining the first communication link with the serving base station, wherein the ranging procedure comprises attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station. The method also includes being released from the serving base station in response to a handover complete status message from the selected target base station to the serving base station, or resuming. normal communication with the serving base station if the handover fails with =the selected target base station.
The serving BS 12 selects one of the neighboring handover target BSs 13 and 14 according to the response messages for the handover pre-notification and transmits a handover confirm message (HO-confirm) to the selected target BS 13 or 14 (S116). The serving BS 12 then transmits a handover response message (MOB-BSHO-RSP), including information pertaining to the selected handover target BS, to the MSS 11 (S117). The MSS
11 receives the handover response message and transmits a handover indicator message (MOB-HO-IND) to release a connection from the MSS 11 to the serving BS 12 (S118).
Upon receipt of the handover indicator message from the MSS 11, the serving BS
releases its connection to the MSS 11 (S119).
1 5 The MSS 11 then executes a fast ranging (Fast Ranging_IE), a ranging request (RNG-REQ), and a ranging response (RNG-RSP) with the target BS 14 (S120, S121, S122). The target BS 14 becomes the serving BS 14 and the MSS 11 completes an initial network entry execution after handover (S123).
FIG. 2 is a diagram illustrating a handover process requested by a base station (BS).
2 0 Referring to FIG. 2, a serving BS 22 triggers a procedure (trigger-to-release-MSS) to release a connection from an MSS 21 according to a corresponding decision (S210).
The serving BS 22 then transmits a handover pre-notification message (HO-pre-notification) including information required for the handover of the MSS 21 to neighboring handover target BSs 23 and 24 (S211, S212). The handover pre-notification message includes an identifier (MSS identifier) of the MSS 21 requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 23 and 24 receive the handover pre-notification message and transmit a handover pre-notification response message (HO-pre-notification-response) to the serving BS 22 in response to the handover pre-notification message (S213, S214). The handover pre-notification response message may include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 22 then transmits a handover request message to the MSS 21 based on the information received via the handover pre-notification response message (S215). The handover request message includes information pertaining to the target BSs 23 and 24 available for the handover. The MSS 21 then performs a neighboring BS scanning 1 5 procedure to measure quality of signals received by the neighboring target BSs, as recognized via a handover response message (S216). In a case where the target BS 24 is found for the handover is found as a result of the neighboring BS scanning, the MSS 21 transmits a handover response message including target BS information for the handover to the serving BS 22 (S217). The serving BS 22 then transmits a handover confirm message to 2 0 the target BS 24 to which the MSS 21 intends to perform the handover (S218).
The MSS 21 then transmits a handover indicator message (MOB-HO-IND) for releasing a connection from the MSS 21 to the serving BS 22 (S219). Upon receipt of the handover indicator message, the serving BS 22 releases its connection to the (S220).
The MSS 21 then executes a fast ranging (Fast Ranging_IE), a ranging request (RNG-REQ), and a ranging response (RNG-RSP) (S221, S222, S223) with the serving target BS
24 for the handover and then completes an initial network entry execution after handover (S224).
FIG. 3 is a diagram illustrating a process by which an MSS re-enters a former serving BS, such as in the case of a call drop.
Referring to FIG. 3, an MSS 31 performs a scanning procedure to measure qualities of signals transmitted from neighboring BSs (S310). If the MSS determines that a handover needs to be performed based on results of the neighboring BS scanning procedure, the MSS
31 transmits a handover request message (MOB-MSS-HO-REQ) to a serving BS 32 (S311).
The serving BS 32 receives the handover request message and transmits a handover pre-notification message (HO-pre-notification) including information that the MSS 31 has requested a handover to a neighboring BS, such as for example, handover target BSs 33 and 34 (S312, S313). The handover pre-notification message includes an identifier (MSS
identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 33 and 34 receive the handover pre-2 0 notification message and transmit a handover pre-notification response message (HO-pre-notification-response) to the serving BS 32 in response to the handover pre-notification message (S314, S315). The handover pre-notification response message may include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 32 selects one of the neighboring handover target BSs 33 and 34 according to the response messages for the handover pre-notification and transmits a handover confirm message (HO-confirm) to the selected target BS 33 or 34 (S316). The serving BS 32 then transmits a handover response message (MOB-BSHO-RSP) including information pertaining to the target BS for the handover to the MSS 31 (S317).
The MSS
31 receives the handover response message from the serving BS 32 and transmits a handover indicator message (MOB-HO-IND) to release a connection from the MSS
31 to the serving BS 32 (S318). Upon receipt of the handover indicator message, the serving BS
32 releases its connection to the MSS 31 (S319).
SUMMARY
Accordingly, an embodiment of the present invention is directed to handover execution and communication resumption in a wireless access system that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An embodiment of the present invention may provide a method of efficiently resuming communications in a wireless access system when a mobile subscriber station (MSS) returns to a former serving base station (BS) in case of a handover failure.
Additional advantages, objects, and features will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
According to an aspect of the invention, there is provided a method of 5 performing handover operation in a wireless communication system, the method comprising:
communicating with a serving base station through a first communication connection using connection resources, wherein the serving base station retains the connection resources for a mobile subscriber station; receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover 10 response message comprises at least a quality of service capable of being handled by the at least one candidate target base station; determining whether to perform a handover operation in response to the handover response message; if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station; performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station;
transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection resources.
A further aspect of the invention provides a method of performing handover operation in a wireless communication system, the method comprising: receiving a handover request from a mobile subscriber station through a first communication connection using connection resources; transmitting a handover response message to the mobile subscriber station, wherein the handover response message is associated with at least one candidate target base station and comprises at least a quality of service capable of being handled by the 10a at least one candidate target base station; receiving a first handover indicator message from the mobile subscriber station indicating that the mobile subscriber station is to undergo a handover operation to a selected target base station of the at least one candidate target base station; retaining the connection resources related to the mobile subscriber station; receiving a second handover indicator message indicating a handover cancel upon failure of the mobile subscriber station to establish a second communication connection with the selected target base station; and after the receiving of the second handover indicator message, resuming normal communication with the mobile subscriber station using the retained connection resources.
There is also provided a mobile subscriber station in a wireless communication system, the mobile subscriber station comprising: means for communicating with a serving base station through a first communication connection, wherein the serving base station retains connection resources related to the mobile subscriber station; means for receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover response message comprises at least a quality of service capable of being handled by the at least one candidate target base station; means for determining whether to perform a handover operation in response to the handover response message; means for, if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station; means for performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station; means for transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and means for, after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection resources.
10b In one embodiment, a method of performing handover operation in a wireless communication system includes communicating with a serving base station through a first communication link and receiving from the serving base station, handover information associated with at least one candidate target base station, wherein the handover information comprises at least quality of service capable of being handled by the at least one candidate target base station. The method also includes transmitting a handover indicator to the serving base station indicating a handover operation to a selected target base station, wherein the mobile subscriber station determines whether to perform handover in response to the handover information, and performing a ranging procedure with the selected target base station to establish a second communication link with the selected target base station while maintaining the first communication link with the serving base station, wherein the ranging procedure comprises attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station. The method also includes being released from the serving base station in response to a handover complete status message from the selected target base station to the serving base station, or resuming. normal communication with the serving base station if the handover fails with =the selected target base station.
The method may also preferably include receiving a handover response from a serving base station upon the serving base station transmitting a handover confirmation to a handover target base station, wherein the handover response comprises at least quality of service information requested to be handled by the handover target base station. The method may also preferably include, in a mobile subscriber station initiated handover, transmitting a handover request to a serving base station through a first communication link prior to receiving the handover response from the serving base station. The method may also preferably include, in a service base station initiated handover, receiving a handover request from the serving base station prior to transmitting a handover response to the serving base station.
The mobile subscriber station may preferably be released from the serving base station when the handover complete status message indicates successful handover. The mobile subscriber station may preferably resume normal communication with the serving base station when the handover complete status message indicates handover failure.
The step of performing the ranging procedure may preferably include receiving a frame slot allocation from the target base station for a fast ranging, transmitting a ranging request to the target base station using the allotted frame slot, and receiving a ranging response from the target base station.
The handover complete status message from the target base station to the serving base 2 0 station may preferably be an inter-base station backbone message. The handover indicator may preferably include one of (1) serving base station release, (2) handover cancel, and (3) handover rejection.
The mobile subscriber station may preferably be released from the serving base station when the handover complete status message indicates successful handover. The mobile subscriber station may preferably resume normal communication with the serving base station when the handover complete status message indicates handover failure.
The step of performing the ranging procedure may preferably include receiving a frame slot allocation from the target base station for a fast ranging, transmitting a ranging request to the target base station using the allotted frame slot, and receiving a ranging response from the target base station.
The handover complete status message from the target base station to the serving base 2 0 station may preferably be an inter-base station backbone message. The handover indicator may preferably include one of (1) serving base station release, (2) handover cancel, and (3) handover rejection.
In another embodiment, a method of performing handover operation in a wireless communication system includes receiving a handover request from a mobile subscriber station through a first communication link, transmitting a handover pre-notification to a target base station, and transmitting a handover response upon the serving base station receiving a handover confirmation from the target base station. The method also includes receiving a handover indicator from the mobile subscriber station indicating a handover operation to the target base station and performing a setup procedure between the mobile subscriber station and the target base station to establish a second communication link with the target base station while maintaining the first communication link with the serving base station. The method also includes releasing the mobile subscriber station or continuing normal communication with the mobile subscriber station in response to a handover complete status message from the target base station to the serving base station.
In yet another embodiment, a method of performing handover operation in a wireless communication system comprises transmitting a handover pre-notification to a target base station. The method also comprises transmitting a handover response upon the serving base station receiving a handover confirmation from the target base station and transmitting a handover request to a mobile subscriber station that is in communication with the serving base station through a first communication link. The method also comprises receiving a handover response from the mobile subscriber station indicating a handover operation to 2 0 the target base station. The method also comprises performing a setup procedure between the mobile subscriber station and the target base station to establish a second communication link with the target base station while maintaining the first communication link with the serving base station. The method also comprises releasing the.
mobile subscriber station or continuing normal conununication with the mobile subscriber station in response to a handover complete status message from the target base station to the serving base station.
The handover request may preferably comprise a possible handover target base station.
The method may also preferably comprise receiving a handover complete message from the target base station to the serving base station.
The foregoing and other objects, features, aspects and advantages will become more apparent from the following detailed description when taken in conjunction with the 3.0 accompanying drawings. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
FIG. 1 is a diagram illustrating a handover process requested by a mobile subscriber station (MSS).
FIG. 2 is a diagram illustrating a handover process requested by a base station (BS).
In yet another embodiment, a method of performing handover operation in a wireless communication system comprises transmitting a handover pre-notification to a target base station. The method also comprises transmitting a handover response upon the serving base station receiving a handover confirmation from the target base station and transmitting a handover request to a mobile subscriber station that is in communication with the serving base station through a first communication link. The method also comprises receiving a handover response from the mobile subscriber station indicating a handover operation to 2 0 the target base station. The method also comprises performing a setup procedure between the mobile subscriber station and the target base station to establish a second communication link with the target base station while maintaining the first communication link with the serving base station. The method also comprises releasing the.
mobile subscriber station or continuing normal conununication with the mobile subscriber station in response to a handover complete status message from the target base station to the serving base station.
The handover request may preferably comprise a possible handover target base station.
The method may also preferably comprise receiving a handover complete message from the target base station to the serving base station.
The foregoing and other objects, features, aspects and advantages will become more apparent from the following detailed description when taken in conjunction with the 3.0 accompanying drawings. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
FIG. 1 is a diagram illustrating a handover process requested by a mobile subscriber station (MSS).
FIG. 2 is a diagram illustrating a handover process requested by a base station (BS).
FIG. 3 is a diagram illustrating a process by which an MSS re-enters a former serving BS, such as in the case of a call drop.
FIG. 4 is a diagram illustrating a handover process initiated by a MSS, according to one embodiment of the present invention.
FIG. 5 is a diagram illustrating a handover process initiated by a BS, according to one embodiment of the present invention.
FIG. 6 is a diagram illustrating a process by which an MSS resumes communications with a former serving BS, in case of a handover failure, according to one embodiment the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
FIG. 4 is a diagram illustrating a handover process initiated by a mobile subscriber station (MSS), according to one embodiment of the present invention.
Referring to FIG. 4, an MSS 41 performs a scanning procedure to measure qualities of signals transmitted from neighboring base stations (BSs) (S410). If the MSS 41 determines that a handover needs to be performed based on results of the neighboring BS
scanning 2 0 procedure, the MSS 41 may transmit a handover request message (e.g., MOB-MSS-HO-REQ) to a serving BS 42 (S411).
The serving BS 42 receives the handover request message and may transmit a handover pre-notification message (e.g., HO-pre-notification) to a neighboring BS, such as for example, handover target BSs (target BSs) 43 and 44 (S412, S413). The handover pre-notification message may preferably include information that the MSS 41 has requested a handover, as well as an identifier (MSS identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 43 and 44 may receive the handover pre-notification message and may transmit a handover pre-notification response message (e.g., HO-pre-notification-response) to the serving BS 42 in response to the handover pre-notification message (S414, S415). The handover pre-notification response message may preferably include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 42 may select one of the neighboring handover target BSs 43 and 15 based on the handover pre-notification response message and may transmit a handover confirm message (e.g., HO-confirm) to the selected target BS 43 or 44 (S416).
The serving BS 42 may transmit a handover response message (e.g., MOB-BSHO-RSP), including information pertaining to the possible handover target BS, to the MSS 41 (S417). The MSS
41 receives the handover response message and may transmit a handover indicator message (e.g., MOB-HO-IND) to release a connection from the MSS 41 to the serving BS
42 (S418).
An exemplary configuration of the handover indicator message is shown in Table 1.
[Table 1]
FIG. 4 is a diagram illustrating a handover process initiated by a MSS, according to one embodiment of the present invention.
FIG. 5 is a diagram illustrating a handover process initiated by a BS, according to one embodiment of the present invention.
FIG. 6 is a diagram illustrating a process by which an MSS resumes communications with a former serving BS, in case of a handover failure, according to one embodiment the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
FIG. 4 is a diagram illustrating a handover process initiated by a mobile subscriber station (MSS), according to one embodiment of the present invention.
Referring to FIG. 4, an MSS 41 performs a scanning procedure to measure qualities of signals transmitted from neighboring base stations (BSs) (S410). If the MSS 41 determines that a handover needs to be performed based on results of the neighboring BS
scanning 2 0 procedure, the MSS 41 may transmit a handover request message (e.g., MOB-MSS-HO-REQ) to a serving BS 42 (S411).
The serving BS 42 receives the handover request message and may transmit a handover pre-notification message (e.g., HO-pre-notification) to a neighboring BS, such as for example, handover target BSs (target BSs) 43 and 44 (S412, S413). The handover pre-notification message may preferably include information that the MSS 41 has requested a handover, as well as an identifier (MSS identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 43 and 44 may receive the handover pre-notification message and may transmit a handover pre-notification response message (e.g., HO-pre-notification-response) to the serving BS 42 in response to the handover pre-notification message (S414, S415). The handover pre-notification response message may preferably include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 42 may select one of the neighboring handover target BSs 43 and 15 based on the handover pre-notification response message and may transmit a handover confirm message (e.g., HO-confirm) to the selected target BS 43 or 44 (S416).
The serving BS 42 may transmit a handover response message (e.g., MOB-BSHO-RSP), including information pertaining to the possible handover target BS, to the MSS 41 (S417). The MSS
41 receives the handover response message and may transmit a handover indicator message (e.g., MOB-HO-IND) to release a connection from the MSS 41 to the serving BS
42 (S418).
An exemplary configuration of the handover indicator message is shown in Table 1.
[Table 1]
Syntax Size Notes MOB HO IND Message _ _ _ Format(){
Management Message Type 8 bits =56 reserved 6 bits Reserved; shall be set to zero HO_IND_type 2 bits 00: Serving BS release 01: HO cancel 10: HO rejection 11: Resume Communication Target_BS _ID 48 Applicable only when bits HO _ IND _type is set to 00 or HAMC Tuple 21 bytes The handover indicator message (MOB_HO_IND) may include information to notify the former serving BS 42 to resume communication with the MSS 41 if the handover of the MSS 41 to the handover target BS fails.
Before the connection to the MSS 41 to the serving BS 42 is released, the MSS
Management Message Type 8 bits =56 reserved 6 bits Reserved; shall be set to zero HO_IND_type 2 bits 00: Serving BS release 01: HO cancel 10: HO rejection 11: Resume Communication Target_BS _ID 48 Applicable only when bits HO _ IND _type is set to 00 or HAMC Tuple 21 bytes The handover indicator message (MOB_HO_IND) may include information to notify the former serving BS 42 to resume communication with the MSS 41 if the handover of the MSS 41 to the handover target BS fails.
Before the connection to the MSS 41 to the serving BS 42 is released, the MSS
may preferably execute a fast ranging (e.g., Fast Ranging_IE), a ranging request (e.g., RNG-REQ), and a ranging response (e.g., RNG-RSP) with the target BS selected for the handover (S419, S420, S421). In the embodiment, the target BS 44 is selected for the handover. The ranging request may preferably require uplink synchronization between the MSS 41 and the target BS 44. The fast ranging may preferably comprise a frame slot allocation by the target base station 44 to enable the MSS 41 to use the allotted frame slot for performance of fast ranging.
In one embodiment, if the handover is successfully performed, the handover target BS
44 may transmit a handover result to the serving BS 42 via a handover complete message -(e.g., HO-Complete). The former serving BS 42 may preferably recognize the successful completion of the handover via the handover complete message (S422) and may release the serving BS's 42 connection to the MSS 41 (S423). Execution of initial network entry may then be completed (S424).
An exemplary configuration of the handover complete message is shown in Table 2.
[Table 2]
Field = Size Notes Global Header 152 bits MSS unique 48 48-bit unique identifier used by MSS
identifier bits on initial network entry Reason 8 bits #0: Successful Handover #1: Handover Failure due to xxx #2: Handover failure due to yyy #3-7: reserved Security field TBD A
means to authenticate this message The handover complete message may preferably be an inter-base station backbone message to provide notification of a handover state of the MSS 41 from a new serving BS
to the former serving BS 42. Using the handover complete message, the former serving BS
42 may determine whether the MSS 41 has completed the handover to the handover target BS 44. In a case where there is a handover failure, the reason for the handover failure (failure reason) may preferably be set to be delivered to the former serving BS 42. The failure reason may be, for example, a call drop that causes the MSS 41 to fail in accessing the handover target BS 44.
In the event that the handover process is completed, the former serving BS 42 may maintain resources and information associated with the MSS 41 for a predetermined time duration (where there is no instruction from the new serving BS 44).
FIG. 5 is a diagram illustrating a handover process initiated by a BS, according to one embodiment of the present invention.
Referring to FIG. 5, a serving BS 52 triggers a procedure (e.g., trigger-to-release-MSS) to release a connection from an MSS 51 according to a corresponding determination (S510).
The serving BS 52 may transmit a handover pre-notification message (e.g., HO-pre-notification) including information required for the handover of the MSS 51 to neighboring handover target BSs 53 and 54 (S511, S512). The handover pre-notification message may include an identifier (MSS identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 53 and 54 may receive the handover pre-notification message and may transmit a handover pre-notification response message (e.g., HO-pre-notification-response) to the serving BS 52 in response to the handover pre-notification message (S513, S514). The handover pre-notification response message may preferably include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
1 0 The serving BS 52 may preferably transmit a handover response message to the MSS
51 based on the information received via the handover pre-notification response message (S515). The handover response message may preferably include information pertaining to the target BSs 53 and 54 available for the handover. The MSS 51 may preferably perform a neighboring BS scanning procedure to measure quality of received signals on the neighboring target BSs, recognized via the handover response message (S516).
In another embodiment, in a case where the neighboring BS scanning procedure finds the target BS 54 for the handover, the MSS 51 may transmit a handover response message including target BS information for the handover to the serving BS 52 (S517).
The serving BS 52 also may transmit a handover confirm message to the target BS 54, with which the 2 0 MSS 51 determines to perform the handover (S518).
The MSS 51 may transmit a handover indicator message (e.g., MOB-HO-1ND) to release a connection from the MSS 51 to the serving BS 52 (S519). The handover indicator =
message may preferably be configured as shown in Table 1.
Before the connection of the MSS 51 to the serving BS 52 is released, the MSS
may preferably execute a fast ranging (e.g., Fast Ranging_IE), a ranging request (e.g., RNG-REQ), and a ranging response (e.g., RNG-RSP) with the serving target BS 54 for the handover (S520, S521, S522).
In yet another embodiment, if the handover is successfully performed, the handover target BS 54 may transmit a handover reqult to the serving BS 52 via a handover complete message (e.g., HO-Complete) (S523). The handover complete message may preferably be configured as shown in Table 2. The former serving BS 52 may preferably recognize successful completion of the handover via the handover complete message and may release its connection to the MSS 51 (S524). Execution of initial network entry may then be completed (S525).
FIG. 6 is a diagram illustrating a process by which an MSS resumes communications with a former serving BS, in case of a handover failure, according to one embodiment the present invention. The handover failure may be due to, for example, a call drop or other failure reason.
Referring to FIG. 6, an MSS 61 performs a scanning procedure to measure qualities of signals transmitted from neighboring BSs (S610). If the MSS 61 determines that a handover needs to be performed based on results of the neighboring BS scanning procedure, the MSS
61 may preferably transmit a handover request message (e.g., MOB-MSS-HO-REQ) to a serving BS 62 (S611).
The serving BS 62 receives the handover request message and may transmit a handover pre-notification message (e.g., HO-pre-notification) including information that the MSS 61 has requested a handover to a neighboring BS, such as for example, handover target BSs 63 and 64 (S612, S613). The handover pre-notification message may also include an identifier (MSS identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 63 and 64 may receive the handover pre-notification message and may transmit a handover pre-notification response message (e.g., HO-pre-notification-response) to the serving BS 62 in response to the handover pre-notification message (S614, S615). The handover pre-notification response message may preferably include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 62 may preferably select one of the neighboring handover target BSs 63 and 64 based on the handover pre-notification response message and may transmit a handover confirm message (e.g., HO-confirm) to the selected target BS 63 or 64 (S616).
The serving BS 62 may also transmit a handover response message (e.g., MOB-BSHO-RSP), including information pertaining to the handover target BS, to the MSS
61 (S617).
The MSS 61 receives the handover response message and may transmit a handover indicator message (e.g., MOB-HO-IND) to release a connection from the MSS 61 to the serving BS 62 (S618).
In still another embodiment, when the MSS 61 attempts to connect to the handover target BS 64, a handover failure, such as for example a call drop, occurs (S619). The MSS
=
61 may preferably recognize the handover failure and may notify the handover target BS 64.
The MSS 61 may also cancel the handover from the former serving BS 62 and may transmit a message to resume communications with the former serving BS 62.
Because the connection between the serving BS 62 and the MSS 61 was not yet released, the may maintain die connection with the serving BS 62 without executing a procedure for re-entering the serving BS 62. Thus, although the handover attempt failed, the MSS 61 may maintain the connection with the serving BS 62 without executing a procedure for re-entering the serving BS 62. In order to resume communications with the former serving BS
62, the exemplary handover indicator message shown in Table 1 may preferably be used (S620).
In one embodiment, a method of performing handover operation in a wireless communication system includes communicating with a serving base station through a first communication link and receiving from the serving base station, handover information associated with at least one candidate target base station, wherein the handover information comprises at least quality of service capable of being handled by the at least one candidate target base station. The method also includes transmitting a handover indicator to the serving base station indicating a handover operation to a selected target base station, wherein the mobile subscriber station determines whether to perform handover in response to the handover information, and performing a ranging procedure with the selected target base station to establish a second communication link with the selected target base station while maintaining the first communication link with the serving base station, wherein the ranging procedure comprises attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station. The method also includes being released from the serving base station in response to a handover complete status message from the selected target base station to the serving base station, or resuming normal communication with the serving base station if the handover fails with the selected target base station.
The method may also preferably include receiving a handover response from a serving base station upon the serving base station transmitting a handover confirmation to a handover target base station, wherein the handover response comprises at least quality of service information requested to be handled by the handover target base station. The method may also preferably include, in a mobile subscriber station initiated handover, transmitting a handover request to a serving base station through a first communication link prior to receiving the handover response from the serving base station. The method may also preferably include, in a service base station initiated handover, receiving a handover request from the serving base station prior to transmitting a handover response to the serving base station.
The mobile subscriber station may preferably be released from the serving base station when the handover complete status message indicates successful handover. The mobile subscriber station may preferably resume normal communication with the serving base station when the handover complete status message indicates handover failure.
The step of performing the ranging procedure may preferably include receiving a 2 0 frame slot allocation from the target base station for a fast ranging, transmitting a ranging request to the target base station using the allotted frame slot, and receiving a ranging response from the target base station.
The handover complete status message from the target base station to the serving base station may preferably be an inter-base station backbone message. The handover indicator may preferably include one of (1) serving base station release, (2) handover cancel, and (3) handover rejection.
In another embodiment, a method of performing handover operation in a wireless communication system includes receiving a handover request from a mobile subscriber station through a first communication link, transmitting a handover pre-notification to a target base station, and transmitting a handover response upon the serving base station receiving a handover confirmation from the target base station. The method also includes 1 o receiving a handover indicator from the mobile subscriber station indicating a handover operation to the target base station and performing a setup procedure between the mobile subscriber station and the target base station to establish a second communication link with the target base station while maintaining the first communication link with the serving base station. The method also includes releasing the mobile subscriber station or continuing normal communication with the mobile subscriber station in response to a handover complete status message from the target base station to the serving base station.
In yet another embodiment, a method of performing handover operation in a wireless communication system comprises transmitting a handover pre-notification to a target base station. The method also comprises transmitting a handover response upon the serving base 2 0 station receiving a handover confirmation from the target base station and transmitting a handover request to a mobile subscriber station that is in communication with the serving base station through a first communication link. The method also comprises receiving a =
handover response from the mobile subscriber station indicating a handover operation to the target base station. The method also comprises performing a setup procedure between the mobile subscriber station and the target base station to establish a second communication link with the target base station while maintaining the first communication link with the serving base station. The method also comprises releasing the mobile subscriber station or continuing normal communication with the mobile subscriber station in response to a handover complete status message from the target base station to the serving base station.
The handover request may preferably comprise a possible handover target base station.
The method may also preferably comprise receiving a handover complete message from the target base station to the serving base station.
Accordingly, the present invention may efficiently execute a handover and/or resume communications in a wireless access system when a mobile subscriber station (MSS) returns to a former serving base station (BS), in a case of a failed handover.
It will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
= INDERSTRIAL APPLICABILITY
The present invention can be applied to a broadband wireless access system
In one embodiment, if the handover is successfully performed, the handover target BS
44 may transmit a handover result to the serving BS 42 via a handover complete message -(e.g., HO-Complete). The former serving BS 42 may preferably recognize the successful completion of the handover via the handover complete message (S422) and may release the serving BS's 42 connection to the MSS 41 (S423). Execution of initial network entry may then be completed (S424).
An exemplary configuration of the handover complete message is shown in Table 2.
[Table 2]
Field = Size Notes Global Header 152 bits MSS unique 48 48-bit unique identifier used by MSS
identifier bits on initial network entry Reason 8 bits #0: Successful Handover #1: Handover Failure due to xxx #2: Handover failure due to yyy #3-7: reserved Security field TBD A
means to authenticate this message The handover complete message may preferably be an inter-base station backbone message to provide notification of a handover state of the MSS 41 from a new serving BS
to the former serving BS 42. Using the handover complete message, the former serving BS
42 may determine whether the MSS 41 has completed the handover to the handover target BS 44. In a case where there is a handover failure, the reason for the handover failure (failure reason) may preferably be set to be delivered to the former serving BS 42. The failure reason may be, for example, a call drop that causes the MSS 41 to fail in accessing the handover target BS 44.
In the event that the handover process is completed, the former serving BS 42 may maintain resources and information associated with the MSS 41 for a predetermined time duration (where there is no instruction from the new serving BS 44).
FIG. 5 is a diagram illustrating a handover process initiated by a BS, according to one embodiment of the present invention.
Referring to FIG. 5, a serving BS 52 triggers a procedure (e.g., trigger-to-release-MSS) to release a connection from an MSS 51 according to a corresponding determination (S510).
The serving BS 52 may transmit a handover pre-notification message (e.g., HO-pre-notification) including information required for the handover of the MSS 51 to neighboring handover target BSs 53 and 54 (S511, S512). The handover pre-notification message may include an identifier (MSS identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 53 and 54 may receive the handover pre-notification message and may transmit a handover pre-notification response message (e.g., HO-pre-notification-response) to the serving BS 52 in response to the handover pre-notification message (S513, S514). The handover pre-notification response message may preferably include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
1 0 The serving BS 52 may preferably transmit a handover response message to the MSS
51 based on the information received via the handover pre-notification response message (S515). The handover response message may preferably include information pertaining to the target BSs 53 and 54 available for the handover. The MSS 51 may preferably perform a neighboring BS scanning procedure to measure quality of received signals on the neighboring target BSs, recognized via the handover response message (S516).
In another embodiment, in a case where the neighboring BS scanning procedure finds the target BS 54 for the handover, the MSS 51 may transmit a handover response message including target BS information for the handover to the serving BS 52 (S517).
The serving BS 52 also may transmit a handover confirm message to the target BS 54, with which the 2 0 MSS 51 determines to perform the handover (S518).
The MSS 51 may transmit a handover indicator message (e.g., MOB-HO-1ND) to release a connection from the MSS 51 to the serving BS 52 (S519). The handover indicator =
message may preferably be configured as shown in Table 1.
Before the connection of the MSS 51 to the serving BS 52 is released, the MSS
may preferably execute a fast ranging (e.g., Fast Ranging_IE), a ranging request (e.g., RNG-REQ), and a ranging response (e.g., RNG-RSP) with the serving target BS 54 for the handover (S520, S521, S522).
In yet another embodiment, if the handover is successfully performed, the handover target BS 54 may transmit a handover reqult to the serving BS 52 via a handover complete message (e.g., HO-Complete) (S523). The handover complete message may preferably be configured as shown in Table 2. The former serving BS 52 may preferably recognize successful completion of the handover via the handover complete message and may release its connection to the MSS 51 (S524). Execution of initial network entry may then be completed (S525).
FIG. 6 is a diagram illustrating a process by which an MSS resumes communications with a former serving BS, in case of a handover failure, according to one embodiment the present invention. The handover failure may be due to, for example, a call drop or other failure reason.
Referring to FIG. 6, an MSS 61 performs a scanning procedure to measure qualities of signals transmitted from neighboring BSs (S610). If the MSS 61 determines that a handover needs to be performed based on results of the neighboring BS scanning procedure, the MSS
61 may preferably transmit a handover request message (e.g., MOB-MSS-HO-REQ) to a serving BS 62 (S611).
The serving BS 62 receives the handover request message and may transmit a handover pre-notification message (e.g., HO-pre-notification) including information that the MSS 61 has requested a handover to a neighboring BS, such as for example, handover target BSs 63 and 64 (S612, S613). The handover pre-notification message may also include an identifier (MSS identifier) of the MSS requesting the handover, connection parameters, capabilities, a required bandwidth, and quality of service information.
Each of the neighboring handover target BSs 63 and 64 may receive the handover pre-notification message and may transmit a handover pre-notification response message (e.g., HO-pre-notification-response) to the serving BS 62 in response to the handover pre-notification message (S614, S615). The handover pre-notification response message may preferably include acknowledgement information pertaining to the handover pre-notification message and capability information pertaining to the requested quality of service.
The serving BS 62 may preferably select one of the neighboring handover target BSs 63 and 64 based on the handover pre-notification response message and may transmit a handover confirm message (e.g., HO-confirm) to the selected target BS 63 or 64 (S616).
The serving BS 62 may also transmit a handover response message (e.g., MOB-BSHO-RSP), including information pertaining to the handover target BS, to the MSS
61 (S617).
The MSS 61 receives the handover response message and may transmit a handover indicator message (e.g., MOB-HO-IND) to release a connection from the MSS 61 to the serving BS 62 (S618).
In still another embodiment, when the MSS 61 attempts to connect to the handover target BS 64, a handover failure, such as for example a call drop, occurs (S619). The MSS
=
61 may preferably recognize the handover failure and may notify the handover target BS 64.
The MSS 61 may also cancel the handover from the former serving BS 62 and may transmit a message to resume communications with the former serving BS 62.
Because the connection between the serving BS 62 and the MSS 61 was not yet released, the may maintain die connection with the serving BS 62 without executing a procedure for re-entering the serving BS 62. Thus, although the handover attempt failed, the MSS 61 may maintain the connection with the serving BS 62 without executing a procedure for re-entering the serving BS 62. In order to resume communications with the former serving BS
62, the exemplary handover indicator message shown in Table 1 may preferably be used (S620).
In one embodiment, a method of performing handover operation in a wireless communication system includes communicating with a serving base station through a first communication link and receiving from the serving base station, handover information associated with at least one candidate target base station, wherein the handover information comprises at least quality of service capable of being handled by the at least one candidate target base station. The method also includes transmitting a handover indicator to the serving base station indicating a handover operation to a selected target base station, wherein the mobile subscriber station determines whether to perform handover in response to the handover information, and performing a ranging procedure with the selected target base station to establish a second communication link with the selected target base station while maintaining the first communication link with the serving base station, wherein the ranging procedure comprises attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station. The method also includes being released from the serving base station in response to a handover complete status message from the selected target base station to the serving base station, or resuming normal communication with the serving base station if the handover fails with the selected target base station.
The method may also preferably include receiving a handover response from a serving base station upon the serving base station transmitting a handover confirmation to a handover target base station, wherein the handover response comprises at least quality of service information requested to be handled by the handover target base station. The method may also preferably include, in a mobile subscriber station initiated handover, transmitting a handover request to a serving base station through a first communication link prior to receiving the handover response from the serving base station. The method may also preferably include, in a service base station initiated handover, receiving a handover request from the serving base station prior to transmitting a handover response to the serving base station.
The mobile subscriber station may preferably be released from the serving base station when the handover complete status message indicates successful handover. The mobile subscriber station may preferably resume normal communication with the serving base station when the handover complete status message indicates handover failure.
The step of performing the ranging procedure may preferably include receiving a 2 0 frame slot allocation from the target base station for a fast ranging, transmitting a ranging request to the target base station using the allotted frame slot, and receiving a ranging response from the target base station.
The handover complete status message from the target base station to the serving base station may preferably be an inter-base station backbone message. The handover indicator may preferably include one of (1) serving base station release, (2) handover cancel, and (3) handover rejection.
In another embodiment, a method of performing handover operation in a wireless communication system includes receiving a handover request from a mobile subscriber station through a first communication link, transmitting a handover pre-notification to a target base station, and transmitting a handover response upon the serving base station receiving a handover confirmation from the target base station. The method also includes 1 o receiving a handover indicator from the mobile subscriber station indicating a handover operation to the target base station and performing a setup procedure between the mobile subscriber station and the target base station to establish a second communication link with the target base station while maintaining the first communication link with the serving base station. The method also includes releasing the mobile subscriber station or continuing normal communication with the mobile subscriber station in response to a handover complete status message from the target base station to the serving base station.
In yet another embodiment, a method of performing handover operation in a wireless communication system comprises transmitting a handover pre-notification to a target base station. The method also comprises transmitting a handover response upon the serving base 2 0 station receiving a handover confirmation from the target base station and transmitting a handover request to a mobile subscriber station that is in communication with the serving base station through a first communication link. The method also comprises receiving a =
handover response from the mobile subscriber station indicating a handover operation to the target base station. The method also comprises performing a setup procedure between the mobile subscriber station and the target base station to establish a second communication link with the target base station while maintaining the first communication link with the serving base station. The method also comprises releasing the mobile subscriber station or continuing normal communication with the mobile subscriber station in response to a handover complete status message from the target base station to the serving base station.
The handover request may preferably comprise a possible handover target base station.
The method may also preferably comprise receiving a handover complete message from the target base station to the serving base station.
Accordingly, the present invention may efficiently execute a handover and/or resume communications in a wireless access system when a mobile subscriber station (MSS) returns to a former serving base station (BS), in a case of a failed handover.
It will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
= INDERSTRIAL APPLICABILITY
The present invention can be applied to a broadband wireless access system
Claims (7)
1. A method of performing handover operation in a wireless communication system, the method comprising:
communicating with a serving base station through a first communication connection using connection resources, wherein the serving base station retains the connection resources for a mobile subscriber station;
receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover response message comprises at least a quality of service capable of being handled by the at least one candidate target base station;
determining whether to perform a handover operation in response to the handover response message;
if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station;
performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station;
transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection re-sources.
communicating with a serving base station through a first communication connection using connection resources, wherein the serving base station retains the connection resources for a mobile subscriber station;
receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover response message comprises at least a quality of service capable of being handled by the at least one candidate target base station;
determining whether to perform a handover operation in response to the handover response message;
if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station;
performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station;
transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection re-sources.
2. The method of claim 1, further comprising:
in a mobile subscriber station initiated handover, transmitting a handover request to the serving base station through the first communication connection prior to receiving the handover response message from the serving base station.
in a mobile subscriber station initiated handover, transmitting a handover request to the serving base station through the first communication connection prior to receiving the handover response message from the serving base station.
3. The method of claim 1, wherein the performing the ranging procedure comprises:
receiving a frame slot allocation from the selected target base station for a fast ranging;
transmitting a ranging request to the selected target base station using the allotted frame slot; and receiving a ranging response from the selected target base station.
receiving a frame slot allocation from the selected target base station for a fast ranging;
transmitting a ranging request to the selected target base station using the allotted frame slot; and receiving a ranging response from the selected target base station.
4. A method of performing handover operation in a wireless communication system, the method comprising:
receiving a handover request from a mobile subscriber station through a first communication connection using connection resources;
transmitting a handover response message to the mobile subscriber station, wherein the handover response message is associated with at least one candidate target base station and comprises at least a quality of service capable of being handled by the at least one candidate target base station;
receiving a first handover indicator message from the mobile subscriber station indicating that the mobile subscriber station is to undergo a handover operation to a selected target base station of the at least one candidate target base station;
retaining the connection resources related to the mobile subscriber station;
receiving a second handover indicator message indicating a handover cancel upon failure of the mobile subscriber station to establish a second communication connection with the selected target base station; and after the receiving of the second handover indicator message, resuming normal communication with the mobile subscriber station using the retained connection resources.
receiving a handover request from a mobile subscriber station through a first communication connection using connection resources;
transmitting a handover response message to the mobile subscriber station, wherein the handover response message is associated with at least one candidate target base station and comprises at least a quality of service capable of being handled by the at least one candidate target base station;
receiving a first handover indicator message from the mobile subscriber station indicating that the mobile subscriber station is to undergo a handover operation to a selected target base station of the at least one candidate target base station;
retaining the connection resources related to the mobile subscriber station;
receiving a second handover indicator message indicating a handover cancel upon failure of the mobile subscriber station to establish a second communication connection with the selected target base station; and after the receiving of the second handover indicator message, resuming normal communication with the mobile subscriber station using the retained connection resources.
5. A mobile subscriber station in a wireless communication system, the mobile subscriber station comprising:
means for communicating with a serving base station through a first communication connection, wherein the serving base station retains connection resources related to the mobile subscriber station;
means for receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover response message comprises at least a quality of service capable of being handled by the at least one candidate target base station;
means for determining whether to perform a handover operation in response to the handover response message;
means for, if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station;
means for performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station;
means for transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and means for, after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection resources.
means for communicating with a serving base station through a first communication connection, wherein the serving base station retains connection resources related to the mobile subscriber station;
means for receiving from the serving base station, a handover response message associated with at least one candidate target base station, wherein the handover response message comprises at least a quality of service capable of being handled by the at least one candidate target base station;
means for determining whether to perform a handover operation in response to the handover response message;
means for, if the handover is to be performed, transmitting a first handover indicator message to the serving base station indicating that the subscriber station is to undergo the handover operation to a selected target base station of the least one candidate target base station;
means for performing a ranging procedure with the selected target base station to establish a second communication connection with the selected target base station, wherein the ranging procedure comprises receiving ranging information from the selected target base station and attempting to establish an uplink synchronization and power adjustment between the mobile subscriber station and the selected target base station while the serving base station retains the connection resources for the mobile subscriber station;
means for transmitting a second handover indicator message indicating a handover cancel upon a failure to establish the second communication connection with the selected target base station; and means for, after the transmitting of the second handover indicator message, resuming normal communication with the serving base station using the retained connection resources.
6. The mobile subscriber station of claim 5, further comprising:
in a mobile subscriber station initiated handover, means for transmitting a handover request to the serving base station through a first communication connection prior to receiving the handover response from the serving base station.
in a mobile subscriber station initiated handover, means for transmitting a handover request to the serving base station through a first communication connection prior to receiving the handover response from the serving base station.
7. The mobile subscriber station of claim 5, wherein the means for performing the ranging procedure comprises:
means for receiving a frame slot allocation from the selected target base station for a fast ranging;
means for transmitting a ranging request to the selected target base station using the allotted frame slot; and means for receiving a ranging response from the selected target base station.
means for receiving a frame slot allocation from the selected target base station for a fast ranging;
means for transmitting a ranging request to the selected target base station using the allotted frame slot; and means for receiving a ranging response from the selected target base station.
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KR1020040042642A KR100893860B1 (en) | 2004-06-10 | 2004-06-10 | Method for Handover and Resuem Communication in Failing Handover applying to Broadband Wireless Access System |
KR10-2004-0042642 | 2004-06-10 | ||
PCT/KR2005/001766 WO2005120183A2 (en) | 2004-06-10 | 2005-06-10 | Handover execution and communication resumption in wireless access system |
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Families Citing this family (100)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6360100B1 (en) | 1998-09-22 | 2002-03-19 | Qualcomm Incorporated | Method for robust handoff in wireless communication system |
CA2393373A1 (en) | 2002-07-15 | 2004-01-15 | Anthony Gerkis | Apparatus, system and method for the transmission of data with different qos attributes. |
US7668541B2 (en) | 2003-01-31 | 2010-02-23 | Qualcomm Incorporated | Enhanced techniques for using core based nodes for state transfer |
KR100893860B1 (en) | 2004-06-10 | 2009-04-20 | 엘지전자 주식회사 | Method for Handover and Resuem Communication in Failing Handover applying to Broadband Wireless Access System |
KR100877136B1 (en) * | 2005-06-23 | 2009-01-07 | 삼성전자주식회사 | Apparatus and method for processing hand-off between heterogeneous networks in wireless communication system |
KR100703416B1 (en) * | 2005-07-06 | 2007-04-03 | 삼성전자주식회사 | System and method for notifying completion of a network re-entry procedure in a communication system |
US7747252B2 (en) * | 2005-07-12 | 2010-06-29 | Futurewei Technologies, Inc. | Method and system for handover negotiation optimization for wireless system |
GB0514438D0 (en) * | 2005-07-15 | 2005-08-17 | Ip Access Ltd | Cellular radio tellecommunication handover system |
US8982778B2 (en) | 2005-09-19 | 2015-03-17 | Qualcomm Incorporated | Packet routing in a wireless communications environment |
US9078084B2 (en) | 2005-12-22 | 2015-07-07 | Qualcomm Incorporated | Method and apparatus for end node assisted neighbor discovery |
US8509799B2 (en) | 2005-09-19 | 2013-08-13 | Qualcomm Incorporated | Provision of QoS treatment based upon multiple requests |
US9736752B2 (en) | 2005-12-22 | 2017-08-15 | Qualcomm Incorporated | Communications methods and apparatus using physical attachment point identifiers which support dual communications links |
US9066344B2 (en) | 2005-09-19 | 2015-06-23 | Qualcomm Incorporated | State synchronization of access routers |
US8982835B2 (en) | 2005-09-19 | 2015-03-17 | Qualcomm Incorporated | Provision of a move indication to a resource requester |
US20070127475A1 (en) * | 2005-12-05 | 2007-06-07 | Ravi Kuchibhotla | Method and apparatus for switching nodes to a new packet data connection point |
US9083355B2 (en) | 2006-02-24 | 2015-07-14 | Qualcomm Incorporated | Method and apparatus for end node assisted neighbor discovery |
KR20070098385A (en) * | 2006-03-29 | 2007-10-05 | 삼성전자주식회사 | System and method for achieving in communication system |
ATE412326T1 (en) * | 2006-06-20 | 2008-11-15 | Alcatel Lucent | METHOD FOR TRANSFERRING A MOBILE TERMINAL, BASE STATION AND NETWORK THEREFOR |
ES2456690T3 (en) | 2006-06-20 | 2014-04-23 | Interdigital Technology Corporation | Transfer in a wireless communication system |
CN1889785B (en) * | 2006-07-27 | 2010-05-12 | 华为技术有限公司 | Method, system and network for processing switch failure in group switching process |
US8259688B2 (en) | 2006-09-01 | 2012-09-04 | Wi-Lan Inc. | Pre-allocated random access identifiers |
EP2061270A4 (en) * | 2006-09-04 | 2011-10-12 | Panasonic Corp | Communication terminal apparatus, network system and handover method |
CN101536569B (en) * | 2006-10-31 | 2013-07-17 | 交互数字技术公司 | Providing feedback information to target node b during a serving cell change |
KR100970445B1 (en) * | 2006-12-04 | 2010-07-16 | 한국전자통신연구원 | Method of resource management for handover in wireless communication system |
CN101198156B (en) * | 2006-12-08 | 2012-10-31 | 昂达博思公司 | System and method for managing radio base station switch information |
US20080161000A1 (en) * | 2006-12-28 | 2008-07-03 | Nokia Corporation | Apparatus, method and computer program product providing faster handover in mobile wimax system |
KR101386213B1 (en) * | 2007-01-08 | 2014-04-29 | 광운대학교 산학협력단 | Method for deregistering a Relay Station and multi-hop relay system for the same |
AU2007344826B2 (en) * | 2007-01-22 | 2010-12-23 | Fujitsu Limited | Intermittent communication system, base station apparatus, and mobile station apparatus |
KR101348210B1 (en) * | 2007-02-07 | 2014-01-08 | 엘지전자 주식회사 | Handover method and terminal thereof |
JP5222306B2 (en) * | 2007-02-12 | 2013-06-26 | シグラム シンドラー ベタイリグングスゲゼルシャフト エムビーエイチ | “Netsurfing” using Managed Handover (MHO) for VoIP calls |
US8891489B2 (en) * | 2007-03-19 | 2014-11-18 | Qualcomm Incorporated | Handover mechanism that exploits uplink channel quality of a target cell |
US9155008B2 (en) | 2007-03-26 | 2015-10-06 | Qualcomm Incorporated | Apparatus and method of performing a handoff in a communication network |
KR101015739B1 (en) * | 2007-06-05 | 2011-02-22 | 고려대학교 산학협력단 | Handover method in wireless mobile communication system and system therefor |
US8830818B2 (en) | 2007-06-07 | 2014-09-09 | Qualcomm Incorporated | Forward handover under radio link failure |
KR20080109680A (en) * | 2007-06-13 | 2008-12-17 | 삼성전자주식회사 | Handover system in wireless communication system and method thereof |
KR101406363B1 (en) * | 2007-06-22 | 2014-06-12 | 삼성전자주식회사 | Handover method in wireless mobile communication system |
US9094173B2 (en) * | 2007-06-25 | 2015-07-28 | Qualcomm Incorporated | Recovery from handoff error due to false detection of handoff completion signal at access terminal |
CN101345986B (en) * | 2007-07-12 | 2011-05-04 | 华为技术有限公司 | Processing method and base station for switching failure in communication network |
US20090047962A1 (en) * | 2007-08-14 | 2009-02-19 | Rao Anil M | Transfer-of uplink power control parameters during handovers |
CN101415203B (en) * | 2007-10-20 | 2010-06-23 | 华为技术有限公司 | Method and apparatus for determining scanning object |
JP2011501611A (en) * | 2007-10-25 | 2011-01-06 | テレフオンアクチーボラゲット エル エム エリクソン(パブル) | Reduction of handover interruption in WiMax |
EP2214439A1 (en) * | 2007-10-31 | 2010-08-04 | Mitsubishi Electric Corporation | Mobile communication system, base station, mobile station, and base station installation method |
WO2009061151A2 (en) * | 2007-11-07 | 2009-05-14 | Electronics And Telecommunications Research Institute | Method and apparatus for the handover |
KR101472571B1 (en) * | 2007-11-07 | 2014-12-16 | 한국전자통신연구원 | Method and Apparatus for the handover |
US8929909B2 (en) | 2008-01-04 | 2015-01-06 | Sigram Schindler Beteiligungsgesellschaft Mbh | Handover proactive association clearing support method and system |
JP5136090B2 (en) * | 2008-01-30 | 2013-02-06 | 富士通株式会社 | Handover method, mobile terminal, and radio communication system in radio communication system |
KR101512774B1 (en) * | 2008-01-31 | 2015-04-17 | 삼성전자주식회사 | Apparatus and method for performming handover of terminal in wireless communication system |
JP5341108B2 (en) * | 2008-02-05 | 2013-11-13 | テレフオンアクチーボラゲット エル エム エリクソン(パブル) | Handover based on prediction information from the target node |
WO2009111233A1 (en) | 2008-03-04 | 2009-09-11 | Interdigital Patent Holdings, Inc. | Method and apparatus for accessing a random access channel by selectively using dedicated or contention-based preambles during handover |
US8712415B2 (en) | 2008-03-20 | 2014-04-29 | Interdigital Patent Holdings, Inc. | Timing and cell specific system information handling for handover in evolved UTRA |
US8477737B2 (en) * | 2008-03-26 | 2013-07-02 | Alcatel Lucent | System and method to improve uplink coverage in multi-carrier systems |
KR101437693B1 (en) * | 2008-03-31 | 2014-09-03 | 엘지전자 주식회사 | Method of Performing A Handover Procedure |
US20090325573A1 (en) * | 2008-05-20 | 2009-12-31 | Symbol Technologies, Inc. | Methods and apparatus for roaming in a wireless network |
CN104244345A (en) | 2008-06-30 | 2014-12-24 | 交互数字专利控股公司 | Method of executing switching from source cell to target cell, and WTRU |
RU2501186C2 (en) | 2008-07-01 | 2013-12-10 | Самсунг Электроникс Ко., Лтд. | Apparatus and method for handover in wireless communication system |
EP2928236B1 (en) * | 2008-08-11 | 2020-03-11 | Alcatel Lucent | Mobility robustness enhancement in a wireless communication network |
KR101496891B1 (en) * | 2008-08-18 | 2015-03-02 | 삼성전자주식회사 | Method and apparatus for the reduction of serving cell change delay in mobile telecommunication system |
JP5347403B2 (en) * | 2008-09-22 | 2013-11-20 | ソニー株式会社 | Information processing apparatus and method, program, and information processing system |
CN101730158B (en) * | 2008-10-22 | 2013-06-05 | 中兴通讯股份有限公司 | Base station switching method and base station |
US9271204B2 (en) | 2008-11-17 | 2016-02-23 | Qualcomm Incorporated | Mobility management based on radio link failure reporting |
US9491671B2 (en) | 2008-11-17 | 2016-11-08 | Qualcomm Incorporated | Radio link failure reporting |
KR20100072108A (en) * | 2008-12-03 | 2010-06-30 | 삼성전자주식회사 | Method and system providing of emergency call service in a unlicensed mobile access network |
US9357462B2 (en) * | 2008-12-24 | 2016-05-31 | Samsung Electronics Co., Ltd. | Apparatus and method for changing serving cell in a high speed wireless communication system |
US8520632B2 (en) * | 2008-12-29 | 2013-08-27 | Qualcomm Incorporated | Method and apparatus for synchronization during a handover failure in a wireless communication system |
EP2203014B1 (en) * | 2008-12-29 | 2014-09-10 | Alcatel Lucent | Handover method and apparatus thereof |
US8923245B2 (en) * | 2009-03-25 | 2014-12-30 | Lg Electronics Inc. | Method and apparatus for handover in a mobile communication system |
US8666427B2 (en) | 2009-04-08 | 2014-03-04 | Industrial Technology Research Institute | Method for mobile communication and system thereof |
TWI424760B (en) * | 2009-04-08 | 2014-01-21 | Ind Tech Res Inst | Method for mobile communication and system thereof |
ATE512556T1 (en) * | 2009-04-20 | 2011-06-15 | Alcatel Lucent | TRANSFER PROCEDURE |
CN101883406B (en) * | 2009-05-07 | 2015-04-08 | 株式会社Ntt都科摩 | Switching method, mobile terminal and base station |
EP2445258A4 (en) | 2009-06-16 | 2014-06-18 | Fujitsu Ltd | Wireless communication system |
CN101932050B (en) * | 2009-06-19 | 2013-05-22 | 电信科学技术研究院 | Method, system and device for switching user equipment (UE) among nodes on network side |
CN101998542B (en) | 2009-08-11 | 2015-10-21 | 中兴通讯股份有限公司 | To the processing method during handoff failure of closed user group cell and system |
CN102026320B (en) * | 2009-09-22 | 2013-10-09 | 华为终端有限公司 | Network switching method, system and device |
EP2317805B1 (en) * | 2009-10-29 | 2014-04-23 | Mitsubishi Electric R&D Centre Europe B.V. | Method and system for selecting at least one wireless telecommunication device for a coordination session |
US20120230295A1 (en) * | 2009-11-10 | 2012-09-13 | Qualcomm Incorporated | Method and Apparatus to Support HSDPA ACK/CQI Operation During Baton Handover in TD-SCDMA Systems |
CN101990779B (en) * | 2009-11-12 | 2015-04-01 | 高通股份有限公司 | Method and apparatus for correcting power in uplink synchronization in td-scdma handover |
CN102123458A (en) * | 2010-01-11 | 2011-07-13 | 中兴通讯股份有限公司 | Radio link failure processing method and terminal |
CN102123457B (en) * | 2010-01-11 | 2016-04-13 | 中兴通讯股份有限公司 | Changing method and terminal |
CN102714505B (en) * | 2010-01-14 | 2016-02-24 | 诺基亚技术有限公司 | For system, method and apparatus that modulator-demodulator is coordinated |
US8478258B2 (en) * | 2010-03-05 | 2013-07-02 | Intel Corporation | Techniques to reduce false detection of control channel messages in a wireless network |
KR101778958B1 (en) | 2010-03-09 | 2017-09-18 | 삼성전자주식회사 | Communication method of a terminal and a access point for power saving of multiuser |
US8615241B2 (en) | 2010-04-09 | 2013-12-24 | Qualcomm Incorporated | Methods and apparatus for facilitating robust forward handover in long term evolution (LTE) communication systems |
WO2012058608A2 (en) * | 2010-10-29 | 2012-05-03 | Huawei Technologies Co., Ltd. | Design and method to enable single radio handover |
WO2012096505A2 (en) * | 2011-01-11 | 2012-07-19 | 엘지전자 주식회사 | Control apparatus, control target apparatus, and method for operating the control apparatus and the control target apparatus in multiple networks |
US8923864B2 (en) | 2011-05-26 | 2014-12-30 | Sigram Schindler Beteiligungsgesellschaft Mbh | Handover proactive association provisioning support method and system |
US20130044731A1 (en) * | 2011-08-15 | 2013-02-21 | Qualcomm Incorporated | Proactive Feedback Transmissions During Handover Procedures |
US20130107860A1 (en) * | 2011-10-27 | 2013-05-02 | Qualcomm Incorporated | REDUCING SERVICE INTERRUPTION OF VOICE OVER INTERNET PROTOCOL (VoIP) CALLS DUE TO INTER-RADIO ACCESS TECHNOLOGY (RAT) HANDOVER |
US10728819B2 (en) | 2012-01-10 | 2020-07-28 | Nokia Solutions And Networks Oy | Handling handover requests in a communications system |
WO2013170878A1 (en) * | 2012-05-14 | 2013-11-21 | Nokia Siemens Networks Oy | Signaling framework for assistance information |
CN103428783B (en) * | 2012-05-22 | 2018-06-12 | 北京三星通信技术研究有限公司 | The method for supporting detection RLF or handover failure reason |
EP2926595A1 (en) * | 2012-11-27 | 2015-10-07 | Sigram Schindler Beteiligungsgesellschaft mbH | Handover proactive association provisioning support method and system |
CN111491344B (en) * | 2012-11-27 | 2023-04-18 | 西格拉姆申德勒有限公司 | Handover proactive association clearance support method and system |
CN103269357B (en) * | 2013-04-24 | 2016-09-14 | 深圳市金立通信设备有限公司 | A kind of method and device realizing application service High Availabitity |
RU2643006C2 (en) | 2013-05-02 | 2018-01-29 | Институт Нефти И Газа - Панствови Институт Бадавчи | Water-soluble inhibitor of corrosion for protection of operating pipes and pipelines for natural gas and also method of its obtaining |
US9485725B2 (en) * | 2014-06-25 | 2016-11-01 | Qatar University Qstp-B | Methods and system for dynamically switching off/on of base stations |
US10263745B2 (en) * | 2015-03-14 | 2019-04-16 | Qualcomm Incorporated | Reciprocal channel sounding reference signal allocation and configuration |
EP3316630B1 (en) * | 2015-08-07 | 2022-03-30 | Huawei Technologies Co., Ltd. | Time synchronization method, device and system |
WO2018172548A1 (en) * | 2017-03-24 | 2018-09-27 | Telefonaktiebolaget Lm Ericsson (Publ) | Qos flows inactivity counters |
CN109168180B (en) * | 2017-08-11 | 2020-03-10 | 华为技术有限公司 | Communication method, source base station, target base station, core network equipment and terminal equipment |
Family Cites Families (31)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6021333A (en) | 1993-11-01 | 2000-02-01 | Omnipoint Corporation | Method and system for transferring information within a mobile communication system |
US6055427A (en) | 1996-07-18 | 2000-04-25 | Nokia Telecommunications Oy | Hard handoff and a radio system |
JPH10290475A (en) * | 1997-02-12 | 1998-10-27 | Fujitsu Ltd | Mobile communication system |
WO1999055104A1 (en) * | 1998-04-23 | 1999-10-28 | Mitsubishi Denki Kabushiki Kaisha | Mobile radio communication system, communication apparatus for mobile radio communication system, and mobile radio communication method |
DE19900436B4 (en) * | 1999-01-08 | 2016-12-01 | Ipcom Gmbh & Co. Kg | Handover method, mobile station for handover and base station for handover |
JP3338809B2 (en) | 1999-10-26 | 2002-10-28 | 日本電気通信システム株式会社 | Mobile telephone communication system and channel switching method between mobile telephone communication systems |
US6438117B1 (en) | 2000-01-07 | 2002-08-20 | Qualcomm Incorporated | Base station synchronization for handover in a hybrid GSM/CDMA network |
US6542744B1 (en) * | 2000-06-20 | 2003-04-01 | Motorola, Inc. | Handoff in a cellular network |
KR100729425B1 (en) * | 2000-08-09 | 2007-06-15 | 에스케이 텔레콤주식회사 | Handoff method in wireless communication system supporting USTS |
DE60104243T2 (en) * | 2000-08-09 | 2006-06-14 | Sk Telecom Co | Handover procedure in wireless telecommunication systems with USTS support |
CA2423322C (en) | 2000-10-09 | 2008-12-09 | Nokia Corporation | Radio resource management |
KR100464019B1 (en) | 2000-12-29 | 2004-12-30 | 엘지전자 주식회사 | Pronunciation string display method at the time of edit for voice recognizing apparatus |
JP2002232929A (en) | 2001-02-01 | 2002-08-16 | Ntt Docomo Inc | Hand-over control method, mobile station and communication controller |
AU2002305404A1 (en) * | 2001-05-02 | 2002-11-11 | Linkair Communications, Inc. | Pre-synchronization handoff mechanisms for wireless communication networks |
US6961572B2 (en) * | 2001-12-20 | 2005-11-01 | Motorola, Inc. | Method and apparatus for base-initiated, CDMA-dispatch soft handoff |
KR100447339B1 (en) * | 2001-12-28 | 2004-09-07 | 에스케이 텔레콤주식회사 | Hand-over controlling system and method thereof in mobile telecommunication system |
US7110376B2 (en) * | 2002-04-10 | 2006-09-19 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for improved cell detection |
US20040058678A1 (en) | 2002-09-23 | 2004-03-25 | Detorbal Rene Fernand Emile | Method and apparatus for facilitating handovers for a group of mobile radios |
AU2003271881A1 (en) | 2002-10-04 | 2004-04-23 | M-Stack Limited | Access stratum manager |
CN1157969C (en) | 2002-12-13 | 2004-07-14 | 大唐移动通信设备有限公司 | Switching method used in mobile comunication system |
WO2005015842A1 (en) | 2003-08-06 | 2005-02-17 | Matsushita Electric Industrial Co., Ltd. | Terminal device and method for master-slave handover in media access communication system |
KR100689508B1 (en) | 2003-09-04 | 2007-03-02 | 삼성전자주식회사 | Method for performing handover in a communication system |
US8396500B2 (en) | 2003-10-27 | 2013-03-12 | Fujitsu Limted | Connection destination base station determination device |
US8904931B2 (en) * | 2003-11-10 | 2014-12-09 | Day International, Inc. | Printing blanket construction and method of making |
KR100827105B1 (en) | 2004-02-13 | 2008-05-02 | 삼성전자주식회사 | Method and apparatus for ranging to support fast handover in broadband wireless communication system |
AU2005241842B2 (en) * | 2004-05-07 | 2008-08-07 | Samsung Electronics Co., Ltd. | System and method for handover capable of minimizing service delay in broadband wireless access communication system |
KR100893860B1 (en) * | 2004-06-10 | 2009-04-20 | 엘지전자 주식회사 | Method for Handover and Resuem Communication in Failing Handover applying to Broadband Wireless Access System |
US20060166677A1 (en) * | 2005-01-27 | 2006-07-27 | Lucent Technologies, Inc. | Balancing load of cells in inter-frequency handover of wireless communications |
US20060276189A1 (en) * | 2005-04-01 | 2006-12-07 | Interdigital Technology Corporation | Supporting inter-technology handover using IEEE 802.16 handover procedures |
US20090275453A1 (en) * | 2008-04-30 | 2009-11-05 | Yu-Lang Wu | Roller for Various Machines and Apparatus |
US8295775B2 (en) * | 2008-05-01 | 2012-10-23 | Broadcom Corporation | Determining a handoff metric |
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